Flow controlling device for refrigerating systems



c. STEENSTRUP 2,056,022

FLOW CONTROLLING DEVICE FOR REFRIGERATING SYSTEMS Sept; 29, 1936.

Filed Jan. l8, 1936 Inventov: Christian Steensbrwp,

Patented Sept. 29, 1936 UNITED STATES FLOW CONTROLLING DEVICE FORBEFBIGEBATING SYSTEMS Christian Steenstrup, Schenectady, N. Y., assignorto General Electric Company, .a corporation of New York ApplicationJanuary 18, 1936, Serial No. 59,756 10. Claims. (Cl. 138-42) Myinvention relates to flow controlling devices for controlling the flowof refrigerant between the high and low pressure sides of refrigeratingsystems.

A vaporizable liquid refrigerant, such as sulphur dioxide, is ordinarilycirculated through a closed refrigerating system in such manner that itis supplied in liquid form to an evaporator or other cooling unit inwhich the liquid is vaporized by the absorption of heat from articles tobe cooled. The refrigerant thus vaporized then flows to acompressor-condenser unit or the like in which the vaporized refrigerantis first compressed by a suitable compressor and then liquefied by thetransfer of heat therefrom toa cooling medium which flows in heatexchange relationship with the condenser. The refrigerant thus liquefiedin the condenser is again supplied to the cooling unit and the cycle isrepeated and continued until the desired cooling has been effected bythe cooling unit. In such a system it is necessary to provide a pressurereducing device between the condenser, which is on thehigh pressure sideof the system and the evaporator or other cooling unit which is on thelow pressure side of the system, for regulating the flow of liquidrefrigerant from the condenser to the evaporator.

An essential requirement of a satisfactory flow controlling device forthe purpose described above is that it should prevent the flow ofgaseous refrigerant after the liquid refrigerant has passed therethroughor should limit such flow to a very small amount. This requirementarises from the fact that a flow of gaseous refrigerant from the highpressure-side to the low pressure side of the refrigerating systemresults in a loss in capacity and efficiency of the system. At the sametime the flow controlling device must permit a sufficient quantity ofliquid refrigerant to flow therethrough to meet the capacity requirethanfloat valves or other devices having moving parts, which have heretoforebeen used as flow controlling devices between the high and 'low pressuresides of the refrigerating system,

such capillary tubes are nevertheless bulky and susceptible to damagesince such a tube may be easily crushed thus cutting off the flow ofrefrigerant therethrough and rendering the refrigerating systeminoperative.

' It is an object of my invention to provide a flow controlling devicefor controlling the How of refrigerant betweenthe high and low pressuresides of a refrigerating system which has an elongated refrigerantpassage of improved form arranged therein, which substantially preventsthe flowof vaporized refrigerant therethrough while at the same timepermitting a sufficient quantity of liquid refrigerant to flowtherethrough to meet the capacity requirements of the system at thelowest pressure different prevailing between the high and low pressuresides of the system.

It is a further object of my invention to provide a flow controllingdevice for controlling the flow of refrigerant between the high and lowpressure sides of a refrigerating system which is compact, rugged, andeconomical to manufacture; being preferably made of portions of sheetmetal hermetically secured together and having an elongated refrigerantflow controlling passage arranged therebetween.

Further objects and advantages of my invention will become apparent asthe following description proceeds and the features of novelty whichcharacterize my'invention will be pointed out with particularity in theclaims annexed to and forming a part of this specification.

Fora better understandingof my invention, reference may be had to theaccompanying 'drawing in which Fig. 1 is a side elevation partly in 40section of a refrigerating machine provided with a flow controllingdevice embodying'my invention; Fig. 2 is a perspective view of the flowcontrolling device of the refrigerating machine shown in Fig. 1; Fig. 3is a developed view of cally sealed casing l0 mounted on the upper sideof a removable heat insulated top wall ii of the refrigerator cabinetwith which the refrigerating machine is used. Compressed vaporizedrefrigerant, such as sulphur dioxide, is supplied from the compressorcontained in the casing in to a cylindrical sheet metal condenser l2,which surrounds the casing in and is mounted thereon. The compressedgaseous refrigerant thus supplied to the condenser l2 circulates througha helical refrigerant circulatory passage l3 formed in the-condenser l2and is liquefied by the transfer of heat therefrom to the cooling airwhich circulates over the surfaces of the condenser. The cooling aircirculates upwardly over the surfaces of the condenser and between thecon-- denser and the casing ID by natural draft. The refrigerant thusliquefied in the condenser l2 flows through a conduit I4 to acylindrical receiver l5, which is mounted on the wall ll. Liquidrefrigerant accumulated in the receiver l5 flows therefrom through aconduit l6 to a flow controlling device [1, embodying my invention, andis supplied therefrom through a liquid line l8 to a flooded type sheetmetal evaporator IS.

The evaporator I 9 is supported on the lower side of the wall i i in arefrigerator cabinet food storage compartment, the contents of which isto be cooled. The evaporator i9 is provided with a plurality ofrefrigerant circulatory passages 20 which communicate with alongitudinal cylindrical header 2| below the normal liquid leveltherein. The header 2| is maintained about half full of liquidrefrigerant and the refrigerant circulatory passages 20 are thus floodedwith liquid refrigerant. The liquid refrigerant contained in theevaporator i9 is vaporized by the absorption of heat from thecompartment in which the evaporator is located and the refrigerant thusvaporized is collected in the header 2| above the level of the liquidrefrigerant therein. The vaporized refrigerant thus collected in theheader 2| is returned to the compressor in the casing l0 through asuction conduit 22 which communicates with the header 2! above thenormal liquid level therein. This cycle is repeated and continued untilthe temperature of the compartment in which the evaporator I9 is locatedis reduced to the desired value.

The flow controlling device i1 includespcomplementary rectangularportions or sheets of metal 23 and 24, which are preferably made ofcold-rolled steel. A plurality of transverse indentations 25, arrangedin substantially parallel relation, are formed in the sheet 24. Theseindentations 25 are connected in series relation by a plurality oflongitudinal indentations 26 arranged at alternate opposite ends thereofand extending between the adjacent end portions of the transverseindentations 25. It will be noted that the longitudinal indentations 25communicate with the transverse indentations 25 intermediate the endsthereof so that small recesses or pockets 21, arranged in alignment withthe adjacent portions of the transverse indentations 25, are formed atthe opposite ends of the latter- Since the recesses 21 are locatedadjacent the reentrant bends formed in the zigzag or sinuous fluidpassage composed of the indentations 25 and 26, the recesses serve toincrease the tur: bulence of any vaporized refrigerant as it flows fromthe indentations 25 to the indentations 26 or from the indentations 26to the indentations 25. Both the indentations 25 and 26 are ofrelatively small cross-section in order to restrict or substantiallyprevent the flow of vapor therethrough. The indentations 25 and 26 arepreferably about .001 square inch in cross-sectional area when the flowcontrolling device is used with a machine having a capacity about 550 B.t. u.s per hour under an ambient temperature of F. and using sulphurdioxide as a refrigera'nt.

The sheet of metal 23 is preferably flat and somewhat wider than thesheet 24. The longitudinal edges 28 and 29 of the sheet 23 are foldedover the adjacent longitudinal edges of the sheet 24 and the sheets arebrazed or otherwise hermetically sealed together. Complementary semi-'cylindrical indentations 30 and 3| are formed in the sheets of metal 23and 24, respectively. The indentations 30 and 3| are tightly fittedaround the upper end of the liquid line i8 and are brazed or otherwisehermetically sealed thereto. One of the indentations 25 located at anend of the series of such indentations communicates with thecomplementary indentations 30 and 3|. A similar pair of complementarysemi-cylindrical indentations are formed in the sheets'of metal 23 and24 communicating with the one of the indentations 25 located at theopposite end of the series of such indentations. One of these lattercomplementary indentations is shown at 32. These indentations are fittedon the lower end of the conduit l6, being brazed or otherwisehermetically sealed thereto, and thus forming an inlet for the flowcontrolling device H.

In making the flow controlling device I! described above, theindentations 25 and 26 are stamped or otherwise formed in the sheet ofmetal 24. The complementary indentations 3i and 32 are also preferablyformed by the same stamping operation. Complementary indentations arealso stamped or otherwise formed in the sheet of metal 23 to cooperatewith the indentations 3| and 32 to form an inlet and an outlet for theflow controlling device. The sheets of metal 23 and 24 are then arrangedin face contact in which position they conform with each otherthroughout substantially their entire lengths. The edges 23 and 29 ofthe sheet of metal 23 are then folded over the adjacent edges of thesheet of metal 24. The sheets of metal 23 and 24 are then brazedtogether throughout the area of the contacting surfaces thereof orotherwise hermetically secured together. After having been thus securedtogether the sheets of metal 23 and 24 are wound into a helical form,their finished shape being illustrated in Fig. 2. Thermal insulation 33is arranged between adjacent layers of the helically wound sheets ofmetal 23 and 24 in order to prevent the transfer of heat between bodiesof refrigerant passing through the fluid passage made up of theindentations 25 and 26 in the adjacent portions of the flow controllingdeyice. The flow controlling device I! thus formed is preferably mountedin the heat insulation Ha of the refrigerator cabinet wall I I.

The indentations 25, 26 and 21 formed in the sheet 24 cooperate with theadjacent portions of the sheet 23 to form an elongated sinuous iiowcontrolling refrigerant passage of suflicient length and sinuosity, ascompared to its cross-sectional area, substantially to prevent the flowof vaporized refrigerant therethrough while permitting the quantity ofliquid refrigerant to flow therethrough required by the capacity of thesystem at the lowest pressure diiference existing between the high andlow pressure sides of the system during the .thus enters the recesses21.

normal operation thereof; The pockets or recesses 21 are particularlyuseful in preventing the flow of vaporized refrigerant through thesinuous fluid passage formed by the indentations 25 and 26 in that theturbulence of the vapor which changes direction of flow at the junctionsbetween the indentations 25 and 26 is increased by the recesses 21 intowhich a portion of the vapor flows. When the vapor flows along theindentations 25, it tends to continue in the samedirection of flow andUpon striking the closed ends of the recesses 21, the vapor rebounds andturbulence thereof results. This turbulence is, of course, increased asthe speed of movement of the fluid is increased. When liquid refrigerantis flowing through the sinuous fluid passage formed by the indentations25 and 26, however, much less turbulence is set up therein by therecesses 21 in view of the fact that the liquid ordinarily flows at aslower speed than the vapor flowing through the fluid passage and,consequently, the turbulence set up in the liquid upon a change indirection of its flow is less than in the case of the vapor. The flowcontrolling device, which I have illustrated, is compact and rugged andmay be readily manufactured from sheet metal by well-known andeconomical manufacturing operations.

While I have shown a particular embodiment of my invention in connectionwith a compression type refrigerating machine, especially designed forhousehold use, I do not desire my invention to be limited to theparticular construction shown and described and I intend in the appendedclaims to cover all modifications within the spirit and scope of myinvention.

What I claim as new and desire to secure by Letters Patent of the UnitedStates is: v

1. A flow controlling device for controlling the flow of refr gerantbetween the high and low pressure sides of a refrigerating systemcomprising a member having an elongated fluid passage formed therein ofrelatively small cross section, said fluid passage having a plurality ofreentrant bends formed therein, and said member having a plurality ofrecesses formed therein communicating with said fluid passage adjacentsaid reentrant bends thereof, the outer ends of said recesses beingclosed.

2. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising a member having an elongated fluid passage formed therein ofrelatively small cross section, v

i said fluid passage having a plurality of reentrant bends formedtherein, and said member having a plurality of recesses formed thereinarranged in alignment with adjacent portions of said fluid passages andcommunicating therewith, the outer ends of said recesses being closed.

3. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising a member having a plurality of fluid passages formed thereinand arranged in substantially parallel relation, and means including aplurality of connecting passages formed in said member for connectingsaid fluid passages in series relation, said connecting passages beingarranged at 8.1-: ternate opposite ends of said fluid passages andcommunicating with adjacent end portions thereof intermediate the endsof said fluid passages.

4. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising complementary portions of sheet metal conforming with eachother substantially throughout their length, and means for hermeticallysecuring said portions of sheet metal together, said portions of saidmetal having an elongated fluid passage extending therebetween, saidfluid passage having a plurality of reentrant bends formed therein, saidportions of said metal having a plurality of recesses arrangedtherebetween and communicating with said fluid passage adjacent saidreentrant bends therein, the outer ends of said recesses being closed.

5. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of. a refrigerating systemcomprising complementary helical portions of sheet metal conforming witheach other substantially .throughout the helical portions thereof, and

means for hermetically securing said portions of said sheet metaltogether, said helical portions of sheet metal having an elongated fluidpassage of relatively small cross-section extending therebetween. l

6. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising complementary helical portions of sheet metal conforming witheach other substantially throughout the helical portions thereof, meansfor hermetically securing said portions of sheet metal together, saidhelical portions of sheet metal having an elongated fluid passage of.relatively small cross section extending therebetween, and meansincluding thermal insulation arranged between adjacent layers of saidhelical portions of sheet metal for preventing the transfer of heatbetween bodies of fluid contained in adjacent portions of said fluidpassage.

'7. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising complementary helical portions of sheet metal conforming witheach other substantially throughout the helical portions thereof. andarranged in face contact, at least one of said helical portions of.sheet metal having an elongated sinuous indentation formed therein ofrelatively small cross section, and means for hermetically securing saidhelical portions of sheet metal together. I r

8. A flow controlling" device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising complementary portions of sheet metal conforming with eachother substantially throughout their length and arranged in facecontact, at least-one of said portions of sheet metal having anelongated indentation of relatively small cross section formed therein.said indentation having a plurality of reentrant bends, at least one ofsaid portions of sheet metal having a plurality of recesses thereincommunicating with said indentation adjacent said reentrant bends, theouter ends of said recesses being closed, and means for hermeticallysecuring said portions of sheet metal together.

9. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising complementary portions of sheet metal conforming with eachother substantially throughout their length and arranged in facecontact, at least one of said helical portions of sheet metal having aplurality of indentations therein arranged in substantially parallelrelation, means including a plurality of indentations formed in at leastone of. said portions of sheet metal to provide connecting passages forconnecting said first named indentations in series relation, saidconnecting passages being arranged at alternate opposite ends of saidfirst named indentations and extending between adjacent end portionsthereof, said connecting passages communicating with said first namedindentations intermediate the ends thereof, and means for hermeticallysecuring said portions of sheet metal together.

10. A flow controlling device for controlling the flow of refrigerantbetween the high and low pressure sides of a refrigerating systemcomprising complementary elongated helical portions of sheet metalconforming with each other substantially throughout the helical portionsthereof and arranged in face contact, at least one of said helicalportions of sheet metal having a plurality of transverse indentationsformed therein and arranged in substantially parallel relation, at leastone of said helical portions of sheet metal having a plurality oflongitudinal indentations therein arranged at alternate opposite ends ofsaid transverse indentations and extending between adjacent end portionsthereof, said longitudinal indentations communicating with saidtransverse indentations intermediate the ends thereof, means forhermetically securing said helical portions of sheet metal together, andmeans including thermal insulation arranged between adjacent layers ofsaid helical portions of sheet metal for preventing the transfer of heatbetween bodies of fluid contained in adjacent portions of saidindentations.

CHRISTIAN STEENS'IRUP.

